Percussion fuze



Nov. 12, 968 F. IRION 3,410,214

PERCUSSION FUZE Filed Dec.. G, 1966 4 Sheets-Sheet l Fil Nov. 12, 1968 F.1RloN PERCUSSION FUZE 4 Sheets-Sheet 2 Filed DeG.

Nov. 12, 1968 F. lRxoN 3,410,214

PERCUSSON FUZE K 4 SheetsSheet 5 Filed Dec. 6, 1966 3l i0 6g ,lf/4 39 26a l f 398 24' 2 6b I 25a d '56 nvenr Nov. 12, 1968 F. IRION PERCUSSION FUZE Filed Dec. 6, 1966 4 Sheets-Sheet 4 8 l6ia zo 9" gg f6 5 52 I8 v a 44 If, 57 54 l. 56a "9 55 e# 57a United States Patent Office 3,410,214 PERCUSSION FUZE Ferdinand Irion, Baden, Switzerland, assignor to (lerlikon-Buhrle Holding Ltd., Zurich, Switzerland Filed Dec. 6, 1966, Ser. No. 599,430 Claims priority, application Switzerland, Dec. 6, 1965, 16,798/65 6 Claims. (Cl. 102-78) ABSTRACT F THE DISCLOSURE A percussion fuze having a firing pin, supported axially slidable in the fuse casing is movable against la primer with a carrier for the firing pin spring-loaded in the same direction, which carrier, by means of locking bodies engaging in it and a slidable safety sleeve, when in an armed position is checked against sliding owing to the spring force. There is an impact or inertia body, movable in the casing under the influence of the retardation on impact in order to slide the safety sleeve, and with it a safety device which has a locking component having a locking position for holding back the safety sleeve.

This invention relates to ya percussion fuze for a shell. More particularly the invention relates to a percussion fuze with a safety device which, on discharge of the shell, is only released at the end of an acceleration phase.

An object of this invention is to provide a percussion fuze which responds even if the shell stri-kes the target at a small angle, f for example, with a grazing shot.

A yfurther object of this invention is to obtain a safety device which always gives the same delay times, very reliably and free from outside influences, e.g. from the temperature.

With a known percussion fuze of this kind however, only a safety pin is provided as a safety device, which must be withdrawn before tiring the shell. This safety protection is thus inoperative during the phase of acceleration of the shell, i.e. during the passage down the bore. If in this phase of the motion forces act on the impact body which are directed axially, or across the axis of the gun, then it can be shifted by these forces and thereby cause the fuze to operate.

An object of the invention is to eliminate these disadvantages and produce a percussion fuze wherein the safety device, which responds to the axial acceleration of the shell land frees the safety sleeve owing to the cessation of the acceleration, has a slide containing the primer, slidable at right angles to the firing pin, which is slidable into an operative and an inoperative position, and that the locking component, when the slide is located in the inoperative position, is retained in its locked position lby the latter.

Safety devices are known, which are only released at the end of the acceleration phase. In the case of such a safety device, a slide movable at right angles to the ring pin is provided, which is slidable into an operative and into an inoperative position and is held in its inoperative position by a transport-safety device. On -discharge of the shell, this transport-safety device liberates the slide, so that the slide can move into its operative position under the inuence of a spring. This movement is checked by a cataract of fluid, in order to prevent too-rapid arming of the fuze. Such delaying devices are, however, unreliable and show widely-varying values, owing to their dependence on temperature. These safety -devices are not suitable for percussion fuzes of the kind described above and a further object of the invention is to eliminate the above disadvantages.

A further object is to provide another locking body to 3,410,214 Patented Nov. 12, 1968 check the safety sleeve, which is retained by the locking component mentioned in the locked position, and the safety sleeve can have a coned surface on which the locking body is supported in the locked position. The locking component can have a coned part which, under the influence of a spring, can engage ina corresponding conical recess in the slide located in its inoperative position and thereby prevents the slide from sliding into its operative position during an axial acceleration.

The slide can have a hole, in which the firing pin can engage with the slide in the inoperative position during an axial acceleration of the shell, in order to prevent movement of the slide.

With the above and other objects in view which will become apparent from the detailed description below, three preferred modifications of the invention are shown in the drawings in which:

FIGURE 1 is a longitudinal cross-sectional view of a percussion fuze when in position for transport.

FIGURE 2 is a cross-sectional view taken upon section line II-II looking in the direction of the arrows.

FIGURE 3 is a view similar to FIGURE 1 showing the elements with the tiring pin in armed position.

FIGURE 4 is a longitudinal cross-sectional view of a modication of the fuze with the elements in transport position.

FIGURE 5 is a longitudinal cross-sectional view through a base fuze according to a second modification with the elements in transport position, and

FIGURE 6 is a view similar to FIGURE 5 showing the elements in the position at the moment of firing.

In accordance with FIGURE l, a cap 3 is secured to a fuze body 2 screwed into a shell body 1, which centralizes a bearing body 4 placed on the Ifuze body 2. An intermediate body 5 is supported on the bearing body 4 and supports a carrier guide 6. The bearing Ibody 4, the intermediate body 5 and the carrier guide 6 are held in position by the cap 3 resting againsting the flange 6a of the carrier guide `6. Au axially-symmetrical cavity 7 is bounded by the cap 3 and the body 4, the cylindrical portion 7a of which adjoins cone-shaped spaces both behind and in front.

A groove 8 of rectangular cross-section, at right angles to the fuze axis, is provided in the fuze body 2, in which a prism-shaped slide 9 is slidably supported. The slide 9 contains a primer 10 in a hole parallel to the fuze axis. As can be seen from FIGS. 1 and 2, a groove 11 is provided on an end surface of the slide 9, which has a semicircular bottom portion 11a. The front surface of the slide has a conical recess 12, which is arranged coaxially with the semicircular groove bottom portion 11a. The axis of the primer 10, the axis of the groove bottom portion 11a and the plane of symmetry of the groove 11 lie in the longitudinal plane of symmetry of the slide 9.

Two pins 14 are slidably guided in two holes 13 (FIG. 2), arranged parallel to the longitudinal axis of the slide 9, on which act the springs 15. These springs 15, on the one hand, press the pins 14 against the inside surface of the cap 3 and, on the other hand, the slide 9 against the safety bolt 16 having a guiding portion 16a which is slidably supported in the hole 17 of the -fuze body 2. The bolt 16 rests with the shoulder 16b on a ring-shaped locking plate 18 connected to it, which is supported with its outwardly-projecting tabs 18a on the shoulder 17a of the narrower hole 17b. Furthermore, a pin 19 is secured in the fuze body 2, arranged parallel to the fuze axis and protruding into a hole in the bearing body 4, serving as a stop for the slide 9. A capsule 20a, with a booster charge 20, is screwed into the fuze body 2,. A hole 21 forms a connection between the groove 8 and the capsule 20a.

A i-ring pin 22 is slidably supported in the guide 6,

which is under the pressure of a spring 23, guided in its hole 22a, abutting against the guide 6. In the wall 6b of the hollow cylindrical portion of the guide 6, two balls 24 are supported in radially-arranged holes 6c, the diameter of which is greater than the thickness of the wall. A safety member 25 is slid over the body 6 with its front sleeve-like part 25a, and guided on the outside of the body 6, while its rear end is guided in the hole 4a of the bea-ring body 4. The balls 24, in the transport position of the fuze, on the one hand rest against the wall of the hole 25b in the safety member 25 and on the other hand engage, to make safe, in a rounded hollow groove 26 formed in the circumference of the front portion of the firing pin 22, so that the latter is prevented from rearward movement.

At the place where the balls 24 touch the safety member 25, the hole has a slight constriction 25e and below it an enlargement 25d. The safety member 2S rests with its rear end surface 25e, arranged at right angles to the fuze axis, on an inertia body 27. This body 27 has an outside diameter smaller than the hole 4a in the bearing body and is made with a cone-shaped end surface 27a, tapering to the rear, with the same taper as that of the surface 4b of the bearing body 4, on which it rests.

A locking pin 30 is slidably supported in a hole 2S in the bearing body 4, which widens out to the `rear to the hole 29. This pin 30 has a flange-like enlargement 30a and, adjoining the latter, a coned surface 30h, contracting downwardly, joining the cylindrical end of pin 30. Under the pressure of a spring 34, the surface 30b abuts against the coned surface 12 of the slide 9, made with the same taper. The lower cylindrical end of the locking pin 30 lies coaxially with the rounded groove bottom portion 11a of the slide 9 and is, furthermore, guided in a hole 31 in the fuze body 2. A ball 33 is supported in a transverse hole 32 connecting the hole 28 with the cavity 7, which on the one hand rests against the locking pin 30 and on the other hand against the cone-shaped surface 25;f of the safety member 25, and therewith prevents the latter from forward movement.

The operation of the fuze is as follows:

On discharge of the shell fitted with the fuze from a gun, the pin 16 forming the transport safety device, under the effect of inertia forces, moves to the rear into the hole 17, overcoming the resistance to deformation of the tabs 18a of the locking ring 18, which are thereby folded forwardly, thus clearing the way for the slide 9 into the armed position. Owing to the deformed tabs 18a of the ring, which hook into the wall of the hole, the pin 16 is also held in this position after the end of the acceleration. During the period of acceleration of the shell in the barrel, the locking pin 30 is also pressed with its coned surface 30b against the cone-shaped support 12 of the slide 9. This inertia force, exerted to the rear by the locking pin 30 on the slide 9 is so great that it cannot be overcome by the forward component of the force of the two springs 15 of the slide, transmitted th-rough the coned surface 12 of the slide 9. The slide is securely held in this position until the end of the acceleration period, therefore until the shell leaves the gun barrel. The primer is located outside the -fuze axis forming the axis of rotation of the firing pin 22. After the end of the acceleration period, the springs are, however, able to move the slide 9 and to raise the locking pin 30 sufficiently far against the force of the spring 34 for its coned portion 30h to lie in front of the slide 9. The slide is thereby (in accordance with FIG. l) moved so far to the left that its front face rests against the pin 19 and the primer 10 lies coaxially with the axis of the fuze, below the point of firing pin 22. Only after the slide 9 has attained this armed position, can the spring 34 force the locking pin 30 downwards. The flange 30a of the pin 30, which has a diameter larger than the width of the groove 11 in the slide 9, moves past its right hand end (as in FIG. l) and fixes it in the armed position (FIG. 3). On this backward movement, the front end of the pin 30 leaves the way clear for an outwardlydirected movement of the ball 33 in the transverse hole 32.

During the deceleration of the shell after leaving the muzzle, due to the air resistance, a forwardly-directed inertia force acts on the safety member 25. Furthermore, owing to inaccurate manufacture, eccentric positions of the inertia body 27 can occur which, with spun shell, may result in centrifugal forces acting on it. The forwardlydirected component in this case of the reactionary force exerted by the surface 4b on the inertia body 27 is transmitted to the safety member 25. These forces, namely the inertia force and this reactionary force, are not however suflicient to slide inwardly the balls 24 against the force of the spring 23, transmitted through the point of contact on the groove 26 of the firing pin, and therewith to annul the blocking of the safety member. On the other hand, this is, however, the case when the shell strikes the target.

On vertical impact of the shell, the inertia body 27, forcing in front of it the safety member 25, is thrown forward. In this case, the safety member 25 presses, with its surface 25j, the balls 33 -outwardly into the transverse hole 32. With this forward movement of the safety mem-ber 25, the balls 24 are at the same time liberated which, under the pressure extered by the spring 23, transmitted through the surface of the groove 26 of the firing pin, move outwardly through the holes 6c `and move towards the wall of the hole 25d. Thereby the balls 24 free the tiring pin 22, so that it now moves to the rear under the action of the spring 23 and the point of the firing pin penetrates through the hole 4c in the bearing body to the detonator 10 in the slide 9 so that detonation of the explosive charge of the shell is initiated.

If the shell strikes the target :at a small angle, for example with a grazing shot, then, as FIG. 3 shows, owing to the deflection of the shell from its -original flight path, the body 27 will be slid sideways from the axis of the fuze under the action of inertia forces, whereby it slides at the same time forwardly along the coned surface 4b of the bearing body and there-by, in a similar manner as with vertical impact, through sliding of the safety member 25, frees the firing pin 22 for a rearward movement caused by the spring 23 and brings about detonation of the explosive charge.

A modification of the fuze is shown in FIG. 4. Differing from the version shown in FIGS. 1, 2 and 3, the fuze is also developed for instantaneous response at large angles of impact with the target. For this purpose, an instantaneous-fuze striker 37 is provided, which is arranged in a hole 38 extending to the `rear from the tip of the fuze cap 3 and is screwed to the firing pin proper 2.2'. The sleeve 39, which is slidably supported on the firing pin 22 land forms a part of it, is provided with a groove 26 which has in the front a straight surface 26a, running tangentially into the rounded surface. The sleeve 39 is under the pressure of the spring 40, abutting against the guide 6', while another spring 41, stressed between the head 37a of the instantaneous-fuze striker 37 and the guide 6', tries to press the firing pin 22 with its shoulder 42 against the drilled recess 39a of the sleeve 39. The safety member 25 has a cylindrical through hole 25b.

The safety locking pin 30 is merely provided with a flange-like enlargement 30a at its rear end, with which it albuts against the front surface of the slide 9', which is constructed without a groove, and is solid, at the right hand end (as in FIG. 4). The slide 9' has a drilled hole 43, which is situated in the transport position coaxially with the fuze axis, behind the point of the firing pin 22', protruding into the hole 4c of the bearing body 4'.

The operation of this fuze is 'as follows: on discharge, the firing pin 22', simultaneously with the bolt 16 forming the transporting safety device, moves to the rear under the effect of inertia and penetrates with its point into the hole 43 in the slide 9', where it secures the slide against movement into the armed position during the whole acceleration period, therefore during the passage of the shell down the gun barrel. With this rearward movement of the firing pin 22', the sleeve 39 remains firmly fixed by the balls 24', After the cessation of acceleration, the firing pin, under the pressure of the spring 41, returns back to its origin-al position before discharge. The slide is now moved towards the armed position by the springs 15, after the withdrawal of the firing pin point. During the whole of this movement, the flange 30a', of the safety pin rests against the slide. Only when the armed position has been attained, can the safety pin with the flange 30a :move past the slide to the base of the groove 8, clear the transverse hole 32 with its front portion for the passage of the safety ball 33, and therewith remove the blocking of the safety member 25'. After the removal of the blocking, the safety member, before the impact, still remains held in its safety position, that is, owing to frictional forces which act on it as a result of compressive forces transmitted through the inclined surface 26a, of the sleeve 39 to the balls and thence to the holes 25a.

On impact at ia large striking angle, the instantaneousfuze striker 37 along with the sleeve 39 still secured by the balls 24', is thrown to the rear and therewith the firing pin 22' is thrown against the primer 10, so that detonation of the explosive charge takes place instantaneously on impact. With oblique impact of the shell, sliding of the safety member 25' and freeing of the sleeve 39 by the Vballs takes place through inertia effect in a way analogous to that with the fuze -according to the first version. The balls 24', pressed outwardly through the hole by the inclined surface 26a of the groove, free the sleeve so that the latter is thrown to the rear by thel action of the spring 40, whereby it moves with it the ring pin 22 resting against its shoulder 39a and drives it into the primer 10.

As FIGS. 1 and 4 show, the bearing area of the flange 6a of the guide is small and its thickness is slight. In this way, a breaking point is iformed at the flange 6u, which achieves its purpose when, on impact with the target, the body 5 (FIG. l) or 4' (FIG. 4), with its hole presses :against the safety member 25 or 25', it locks and the guide `6 or 6', after the flange shears olf at this prearranged spot, is driven back. The guide 6 or 6', which is coupled to the firing pin 22 or 22 through the balls 24 or 24', is thereby driven back with the latter and in that Way detonation of the explosive charge is initiated, in spite of the non-occurrence of arming thesafety pin 22 or 22' by the safety member 25 or 25'.

As a third embodiment, a base fuze is shown in FIGS. 5 and 6, in which all the fuze components whose construction and function coincide with those of the components of the fuze shown in FIGS. 1 to 3, are allotted the same reference numbers.

On a cover 45 of the casing 44, a capsule 47 containing the booster charge 20' is secured. By means of a hole 48, this booster charge `20' is in spatial connection with a groove 8" running at right angles to the fuze axis, which forms the guide for the slide 9" and is cut in a fuze body 49 which forms a sleeve-shaped connection between the casing 44 and the base part 50. The ring pin 52 is slidably supported in a sleeve 51, coaxial with the fuze, lying behind the slide `9", supported, against the fuze body 49 on the one hand and the base part 50 on one hand the base part 50 on the other hand. This firing pin 52, which is under the effect of aspring 23 abutting against the Ibase of the sleeve 5-1, is blocked by balls 24" supported in holes 51a in the sleeve 51, engaging in the groove 53 of the pin in a similar manner as with the fuse as in FIGS. 1 to 3, and are held in this safety position by the sleeve 56.

Between the cone-shaped surface 50a, open to the front, of the base part 50 and the ange-like enlargement 56a of the safety sleeve 56, under the pressure of a spring 54 abutting against the fuze body 49, the ring-shaped inertia Qbody 27' is inserted, the outside diameter of which is less than that of the hole 55 in the fuze body 49, the inside diameter of which, on the other hand, is greater than the rear portion of the sleeve 51, which it surrounds. The front bearing surface 27b of the inertia body 27 is di rected at right angles to the axis of the fuze, while its rear surface 27a' is conically bevelled, the angle of opening of the cone corresponding to that of the surface 50a of the base part 50.

In the condition of the -fuze suitable for transporting, shown in FIG. 5, the head 58a of a safety pin 58 lying parallel to the fuze axis, under the pressure of a further spring 57, abutting against the, fuze body 49, rests against the bottom of a groove 59 cut into the rear side of the slide 9", directed parallel to the longitudinal axis of the slide. The safety position of the slide 9" is determined by it being held between the wall of the hole 60 in the casing 44 and the head 16a of the safety bolt 16 projecting into the groove 8".

The operation of the fuze is as follows. On discharge, the safety bolt 16 moves to the rear, out of the path of the slide 9". Until the end of the acceleration period of the shell carrying the fuze, the slide 9" remains in the transport position under the inuence of frictional force, produced by inertia force, acting on it. When the shell has `attained its greatest velocity and has left the barrel, when therefore no acceleration acts any longer, the slide 9 is moved into the armed position by the springs 15, in which the primer 10 lies behind the hole 48, but in front of the point of the firing pin 52, and the left end of the slide (as in FIG. 5) touches the wall of the hole 60` in the casing 44, which accordingly acts also here as the stop limiting the travel of the slide 9". At the end of this slide movement, the head 58a of the safety pin 58 emerges completely from the groove 59 of the slide 9". The pin 58 now moves forward, occupying a position behind the slide 9" and thereby securing it, until it strikes the inner Surface 46 of the cover `45 of the casing 44, whereby it releases the sleeve 56. The latter, however, is held in the position shown in FIG. 5 by the spring 54 and furthermore by the friction acting between the balls 24 and its hole surface 56b, securing the firing pin 52 until impact of the shell, even if during the iiight of the shell towards the target inertia forces, directed across the axis or axially, act on the inertia body 27' and on the sleeve 56.

On impact of the .shell at a large angle of incidence, the sleeve 56 and the inertia body 27, are thrown forward under the effect of inertia forces acting on them, thereby overcoming the resistance of the spring 54, so that the balls are pressed, by forces transmitted by the groove 53 of the ring pin 52, into the hole enlargement 56e of the sleeve 56 and free the firing pin, which is then thrown forward by the spring 23' against the primer 10.

On oblique impact of the shell, as for example if the latter ricochets on the ground at a very small angle of incidence and is thereby subjected to an acceleration acting in the direction of the arrow F in FIG. 6, directed across the axis, the inertia body 27', on its lateral shift, resulting from the inertia force acting on it, is thrown forward through a reaction force transmitted by the coned surface 50a of the base part 50, thereby pushing the lsleeve 56 in front of it, and thus the ring pin is armed in the Way already described and the primer fired.

I claim:

1. A fuze for a projectile comprising a casing having a longitudinal axis, a primer in said casing, a rst spring, a ring pin displaceable under the pressure of said spring in the direction of said longitudinal axis against said primer, said ring pin having a groove, a carrier guide for said firing pin in said casing having radially-arranged holes, locking bodies in said holes engageable with said groove, a slidable safety member having a safety and an arming position, said safety member in its safety position holding said locking bodies in engagement with said groove to secure said firing pin against displacement by said first spring, an inertia body within said casing axially and radially displaceable upon impact for axially displacing said safety member, a locking member having a locking position locking said safety member in said safety position during transport of the projectile against a displacement by said inertia body, a slide displaceable transversely to said longitudinal axis containing .said primer, said slide having a safety and an arming position, a second spring, said locking member being displaceable parallel to Said longitudinal axis under the pressure of said second spring against said slide in its safety position, said slide in its safety position holding said locking member in its locking position, and releasing said locking member to its arming position when axial acceleration of said casing allows said locking member to release said safety member.

2. A fuze as claimed in claim 1 wherein said slide has a conical recess and said locking member has a conical part, .said conical part in the locking position of said slide under the effect of said second spring extending into said conical recess and upon displacement of said slide into arming position is moved out of the conical recess against the force of said second spring.

3. A fuze as claimed in claim 2 wherein a third spring urges said slide to armed position.

4. A fuze .as claimed in claim 1 wherein said safety member has a conical surface and a second locking member is provided to keep said safety member in safety position, said second locking member being held in locking position by said first mentioned locking member when in locking position with Said second locking member abutting said conical lsurface on said safety member.

5. A fuze as set forth in claim 1 wherein said safety member has a coned surface cooperating with said locking member if said locking member is in locking position, said slide having .a hole aligned opposite said ring pin when said slide is located in safety position and said firing pin projects into said hole during acceleration to prevent movement of said slide into armed position during axial acceleration.

6. A fuse as claimed in claim 1 wherein a third spring urges said firing pin away from said primer.

References Cited UNITED STATES PATENTS 1,309,773 7/1919 3 Newell 102-73 2,232,714 2/1941 i Mathsen et al 102-84 2,388,691 11/1945 Horan 102--78 2,871,788 2/1959 Guerne 102-71 3,157,125 11/1964 Lohmann 102-78 FOREIGN PATENTS 1,185,093 1/1965 Germany.

BENJAMIN A. BORCHELT, Primary Examiner.

G. H. GLANZMAN, Assistant Examiner. 

